1. Field of the Invention
The invention relates to a parallel resonant circuit converter having at least one intermediate-circuit inductance which can be biased via two series-connected thryistors of the inverter, and a load which forms the parallel resonant circuit and to which a starting circuit is connected for commutating the current flowing during the biasing to the thyristors which, by including the load, are connected in series in diagonal branches.
2. Discussion of the Prior Art
In a known parallel resonant circuit converter, the starting circuit consists of an auxiliary oscillator which excites the resonant load circuit until the load capacitor has a voltage which is suitable for commutating the preselected starting direct current. Starting by means of such a starting device can take relatively long and is therefore not always suitable for small operating periods.
It is also known to connect a series resonant circuit to the parallel resonant circuit of the load. In order to obtain a successful start with such a starting circuit, it is necessary to transfer an optimum amount of energy from the series resonant circuit to the resonant load circuit. This can be achieved only if the natural frequency and damping have been appropriately selected. Since the natural frequency of the resonant load circuit, however, fluctuates with the load, starting cannot be guaranteed in every case if one and the same starting circuit is used.